Steer-by-Wire Control for Lane Guidance and Haptic Steering Feedback
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Solution Overview
Problem
Current steering systems with mechanical coupling between the steering wheel and steered wheels create conflicts in achieving simultaneous requirements for lane guidance and driver control, limiting the performance of semi-autonomous lane guidance functions.
Innovation Solution
A steer-by-wire steering system with independent control of the steering wheel and wheel steering gear actuators, utilizing two separate controllers to manage steering wheel and wheel steering gear actuator setpoints based on vehicle behavior deviations and environmental inputs, allowing for enhanced lane guidance and driver interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical coupling between steering wheel and steered wheels is used, then driver control is maintained, but lane guidance performance deteriorates due to conflicting actuation goals
Solution Approach 1:
The steering system is segmented into two independent control interfaces: one for the steering wheel actuator and another for the wheel steering gear actuator. This segmentation allows each interface to be optimized for its specific function - the steering wheel interface for driver control and haptic feedback, and the wheel steering gear interface for precise lane guidance execution without mechanical coupling constraints.
Solution Approach 2:
A control unit acts as an intermediary between the steering wheel actuator and the wheel steering gear actuator. This intermediary processes commands from both interfaces and coordinates their operation, enabling independent setpoint determination for each actuator while maintaining system-wide coherence and resolving conflicts between driver control and lane guidance objectives.
2Productivity
If independent control of steering wheel and wheel steering gear actuators is implemented, then lane guidance performance is improved, but system complexity increases
Solution Approach 1:
The control unit serves multiple functions simultaneously: it determines setpoints for both the steering wheel actuator and the wheel steering gear actuator, processes deviations from desired vehicle behavior, generates haptic feedback signals, and coordinates the operation of both actuators. This multi-functionality consolidates complexity into a single intelligent controller rather than distributing it across multiple separate systems.
3Ease of operation
If steering wheel actuator is controlled independently for haptic feedback, then driver interaction is enhanced, but mechanical coupling conflicts arise
Solution Approach 1:
The system implements feedback loops that monitor the actual behavior of the vehicle and compare it to the desired behavior. Based on the deviation detected, the control unit adjusts the setpoints for both the steering wheel actuator and the wheel steering gear actuator. This feedback mechanism ensures that haptic feedback to the driver remains coherent with the actual vehicle response, preventing conflicts between independent actuator controls.
Data Source
AI summary
A method and apparatus is for influencing a vehicle behavior of a vehicle in which a setpoint for a steering wheel actuator of a steering system, in particular of a steer-by-wire steering system, is determined independently of a setpoint for a wheel steering gear actuator, and the steering wheel actuator is actuated depending on the setpoint for the steering wheel actuator. The method further includes determining a setpoint for a wheel steering gear actuator of the steering system independently of the setpoint for the steering wheel actuator, and the wheel steering gear actuator is actuated depending on the setpoint for the wheel steering gear actuator. The setpoint for the steering wheel actuator is determined depending on a target value for influencing the steering wheel actuator.